It is known to apply a highly reflective metallic coating on a military object, such as a satellite or missile, in an attempt to protect that object from a laser beam emanating from a remote high power laser. Such a metallic coating functions by a combination of reflection and ablation. Of course, ablation reduces the reflectance of the coating and increases its absorption. Thus a metallic coating is not well suited to protect the object from multiple laser beam strikes or a single prolonged impingement.
A power laser mirror has been proposed including a substrate fabricated from high purity, small grain powders of refractory material. A highly reflective thin metallic film is adhered to the substrate, and a transparent dielectric film covers the metallic film to protect it from tarnishing. For further information concerning the structure and operation of this mirror, reference can be made to U.S. Pat. No. 4,214,818.
Equipment including an integrating sphere is used to measure the total luminous flux of a light source such as a lamp. The inside surface of the sphere has a diffusely reflecting white finish which integrates the light from the source. The interior finish can be a layer of small particles for achieving multiple scattering of the light. While individual particles are weak scatters, they combine to achieve diffuse-reflectances over 99% for a wide spectral range. Such finishes typically are over 1 mm thick and are limited to a spectral range of 300-2000 nm. Such finishes can be formed by MgO "smokes" or barium oxide paint.